Have a lot of customers -> which design should be chosen (one or multiple instances).

Hi!

I'm a little bit confused with this task, but it should be done.
So, we have a lot of customers who should use SQL server for their applications.
Design is standard and simply:

Customer -> Remote Desktop -> AppServer -> SQL Server

So, now we plan create SQL cluster (active/passive or active/active/passive btw which is preffered?) and we are don't know which design for this solution will be the best.

For example we have 50 customers who wants to use DBE/Reporting/Analysis.
What your offers about SQL design for solve this case?

Thanks!